Method for maintenance of valves included in a subsea production system for oil and gas
US4786209A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 22, 1987 |
| Grant date | Nov 22, 1988 |
| Priority date | — |
| Expiry date | Oct 22, 2007 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21B41/04
- WIPO fieldTransport
- WIPO sectorMechanical engineering
Abstract
The present invention relates to a method for replacing an insert unit included in an insert valve assembly belonging to a subsea production system for gas and oil. In carrying out the method, a manipulator (1) is brought by means of a sheave (2), a hoisting cable (3) and guide wires (4, 5) down to a predetermined location on the bottom of the sea. The manipulator comprises a telescopic arm (15, 16) which is then moved towards and fixed by means of a hook (20) and a lug (21) to a valve tree (17) which supports a valve (22), the insert unit (26) of which is to be unscrewed from the respective valve housing and be replaced. A carriage (18) located in the manipulator and comprising retracting, aligning and fixing devices (32, 33, 34) is brought with the aid of the telescopic arm and a rail, located on the top side of the carriage, towards the valve tree and is fixed to retraction cones (35, 36, 37) mounted on the valve tree. This allows a moment producing tool (31), mounted in the carriage, to grapple that castellated nut (24) which holds together the insert unit and valve housing of the valve. Thereafter, a releasing moment is applied on the castellated nut, whereby the castellated n…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.